Carbon electrode.



G. A. HANSEN.

CARBON ELECTRODE. APPLICATION FILED JULY 23, 1909.

1,019,463. Patented Mar. 5, 1912.

Carbon UNITED STATES PATENT OFFICE.

CHARLES .A. HANSEN, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRI COMPANY, A CORPORATIQN OF NEW YORK.

To all whom it may concern: 7

Be it known that I, CHARLES A. HANSEN, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in. Carbon Electrodes, of which the following is a specification.

My invention relates to carbon electrodes particularly electric furnace electrodes, and it comprises a. process whereby the life of electrodes is materially increawd and their use extended, and it also comprises a novel electric furnace electrode which is the of this process.

The accompanying drawing illustrates a furnace electrode prepared in accordance with my invention.

. It has heretofore been impracticable to use what are'commonly known as carbon electrodes as distinguished fiom graphite electrodes in.electric furnace work, as the working end of the carbon elect-rode when subjected to the high temperature existing in the furnace would continually crack and e sliver off, pieces of the electrode falling into the charge, and the electrode in this manner rapidly disintegrating. For thisreason, it has been necessaryto. convert the carbon electrodes into graphite electrodes at considerable expense.

According to my invention, the carbon electrodes are prepared for use in electric furnace work by being graphitized at their tip, or working end. Carbon electrodes when thus prepared are entirely satisfactolry for furnace work, possibly because the part of the carbon electrode 1n immediate 'proximity to the graphitized tip is con- Specification .ofv Letters Patent.

result Patented Mar. 5,1912.

-Appli cation filed July 23, 1909, Serial No. 509,138.

i verted into graphite when the electrodes are in use by being subjected to the high temperature near the working end, so that as the tip is consumed the adjacent zone of carbon is progressively graphitized, until the entire electrode has been consumed.

My invention may be carried out in any convenient way which will locally raise the tip of the electrode to the graphitizing temperature, say about 3000 C. For example, the electrodes are placed in contact end to end and the point of contact is covered with powdered coke. lVhen acurrent is passed through the electrodes thus in contact the point of contact is raised to a high temperature because of its transition resistance. The coke serves to protect the heated carbon from oxidation. The heating is continued in this manner for about fifteen minutes, or

until the temperature of graphitization has been attained throughout the region to be graphitized.

What I claim as new and desire to secure end with imperfect contact and passing a current through them so as to cause a greater graphitizing tendency at the contacting ends than at other parts of the electrodes.

In witness whereof, I have hereunto set.

my hand this 22nd day of July, 1909.

\ CHARLES A. HANSEN. Witnesses;

BENJAMIN'B. HULL, HELEN .ORFORD. 

